1. Field of the Invention
The present invention relates to an electronic musical instrument, and more particularly to an electronic musical instrument capable of applying touch response effect to each key.
2. Prior Art
Conventionally, the electronic musical instrument as the touch response unit has been proposed in Japanese Patent Laid-Open Publication No. 59-105692. Such proposed electronic musical instrument comprises an initial touch response means and after-touch response means. The initial-touch is the touch response corresponding to the varying speed of depressing pressure at the instant when the key is depressed. The after-touch is the touch response corresponding to the continuous variation of depressing pressure in the period when the key is continuously depressed after the key-depression. The initial touch response means controls tone pitch and tone color which are generated in response to key-depressing speed of depressed key by each key. The after-touch response means controls the tone pitch and tone color of musical tone by each key by varying key-depressing pressure of depressed key.
Such kind of electronic musical instrument is advantageous in that delicate expression of musical tone can be improved, because initial touch effect and after-touch effect can be given to the musical tone by each key.
However, in the case where the above-mentioned touch response unit is applied to so-called electronic musical instrument of complex tone which can simultaneously generate the musical tones having plural tone pitches, each of fingers of player must be moved irregularly so that the effects applied to the musical tones will be heard un-naturally.
For example, in the case where plural keys in accompaniment key area are performed by use of five fingers of player's left hand, all of these fingers can not depress the keys with the same key-depressing pressure in general. Even if all of these five fingers are intended to simultaneously depress the keys with the same key-depressing pressure, the actual key-depressing pressures of the keys must be differed. More specifically, the pressure applied to the key depressed by little finger is the smallest, and other key-depressing pressures of keys tend to become stronger in the order of the third finger, middle finger, forefinger and thumb.
Further, there is an example where the after-touch effect is intended to be simultaneously applied to the keys by use of plural fingers of the player's left hand. In other words, in the state where the chord consisting of tones of "do", "mi" and "so" is generated by use of the player's left hand, the aftertouch effect is applied to each of these three tones. In this case, when the tones of "do", "mi" and "so" are respectively generated by use of the little finger, middle finger and thumb of player's left hand, the key-depressing pressures must be increased in the order of the little finger, middle finger and thumb. Hence, the after-touch effect of the tone "so" having the highest tone pitch is the strongest, that of the tone "mi" having the middle tone pitch is the middle, and that of the tone "do" having the lowest tone pitch is the smallest For this reason, when such chord as a whole must be heard in un-natural manner such that the after-touch response of the higher tone pitch is emphasized.
In general, in the case where the keys are simultaneously performed by use of plural fingers, it is difficult to move the middle-part fingers as similar to the edge-part fingers. Hence, the touch control operation for the middle-part fingers must become un-clear as compared to that for the edge-part fingers.
Meanwhile, in the case where the electronic musical instrument capable of applying the touch response effect to each key is provided with automatic performance means capable of performing with plural performance patterns, the conventional console panel must provide selection switches for exclusively selecting the automatic performance patterns independent of the touch response detecting means of keys. Hence, the constitution of conventional electronic musical instrument must be complicated. In addition, when the player changes over the automatic performance patterns while the keys of the keyboard are performed, the player must temporarily stop performing the keys and then change over the selection switches for the automatic performance patters. This operation is complicated in practice. In addition, since the player must release the keys when the automatic performance pattern is changed, there is a disadvantage in that the generation of musical tones which must be continuously generated is intermittently broken.